How to abbreviate large numbers?

I already have a abbreviation system and it works, but it goes all funky at 100T. Can someone tell me what is going on? Here is my script(I have it in a module script and reference to it in other scripts): (Also, number is the value i'm working with)

local abbreviatednumber = {}
local abb = {
	k = 4,
	M = 7,
	B = 10,
	T = 13,
	Qa = 16,
	Qn = 19,
	Si = 22,
	Sp = 25
}
	function abbreviatednumber:abb(number)
			local text = tostring(math.floor(number))
	local chosenabb
	for abbreviations, digits in pairs(abb) do
		if #text >= digits and #text < (digits + 3) then
			chosenabb = abbreviations
			break
		end
	end
	if chosenabb then
		local digits = abb[chosenabb]
		
		local rounded = math.floor(number / 10 ^ (digits - 2)) * 10 ^ (digits - 2)
		
		text = string.format("%.1f", rounded / 10 ^ (digits - 1))..chosenabb
		
	else
		text = number
	end
	return text
	end

return abbreviatednumber

tostring displays very large numbers in a shortened way, such as 100 trillion as 10e+14. So when using tostring and # to get the 'length' of the number, it gets the text length of the shortened version instead.

Another way to find it, which wouldn't break for large numbers, is to use math.log10. Short summary of log10 (base 10 logarithm):

if y = 10^p, then p = math.log10(y)

So math.log10(1) gives 0, math.log10(10) gives 1, math.log10(100) gives 2 and so on. math.log10(500) will be between 2 and 3, as 500 is between 100 and 1000. Knowing this, one replacement for #tostring(math.floor(number)) is

math.floor(math.log10(number)) + 1

However log10 doesn't accept 0, so you should make a special case if the input is 0 (like returning "0"). If support for negative numbers is needed (as log10 doesn't support them), math.abs(number) can be passed to the math.log10 instead of number.